"For people with known heart disease, it's clear that they benefit from
being on an aspirin," says Jacobson, yet "people shouldn't start taking
it on their own." Talking to a doctor first is essential to make sure
you're not at increased risk of bleeding.

Very Low-Risk Men and Women Who May Not Want Aspirin Therapy

Low-risk people include men under 40 and women under 50. While it helps to
know that aspirin does reduce healthy people's risk of heart disease and
stroke, their risk is low to begin with. And daily aspirin may increase their
risk of internal bleeding. For example, if 1,000 healthy people took an aspirin
daily for about six years:

However, aspirin would cause about three life-threatening gastrointestinal
bleeds.

Unless you have risk factors for heart disease, an aspirin won't help, and
may do harm. Talk to a doctor before taking daily aspirin -- because you
probably shouldn't.

Low to Medium Risk: Your Choice on Aspirin Therapy

So people at high risk should take an aspirin, and people at very low risk
shouldn't. What about everyone in between -- the vast majority of us?

The answer is: it depends. Jacobson suggests putting this question to your
doctor: Am I at high enough cardiovascular risk to justify taking an aspirin,
even with the small but real risk of significant bleeding?

"The more risk factors that you have, the greater the chance that you
will benefit" from daily aspirin, Jacobson tells WebMD.